The present disclosure relates generally to equipment utilized and operations performed in conjunction with well drilling operations and, in an embodiment described herein, more particularly provides for pressure and flow control in drilling operations.
Managed pressure drilling is well known as the art of precisely controlling bottom hole pressure during drilling by utilizing a closed annulus and a means for regulating pressure in the annulus. The annulus is typically closed during drilling through use of a rotating control device (RCD, also known as a rotating control head or rotating blowout preventer) which seals about the drill pipe as it rotates.
The means for regulating pressure in the annulus can include a choke interconnected in the mud return line and, in some applications, a backpressure pump to apply pressure to the annulus while connections are made in the drill pipe string. Unfortunately, use of a backpressure pump requires substantial capital investment, the additional pump takes up scarce space on offshore rigs, the pump output is difficult to control accurately and use of the pump interferes with normal operations on a drilling rig.
Therefore, it may be seen that improvements are needed in the art of controlling pressure and flow in drilling operations. These improvements may include the elimination of a separate backpressure pump in drilling operations, but the improvements could be utilized in conjunction with a backpressure pump, if desired.